Doctor blade structure



' July 13, 1948. c. A. HANINGTON 2,445,140

noc'ron BLADE s'rnuc'runn Filed Oct. 5, 1946 mvmron Cir/mes H HflN/AKiTO/V.

Patented July 13, 1948 UNITED STATES rarer FFICE I 2,465,140 noc'ron BLADE s'riauc'ruaa Charles A. Harrington, Freeport, N. if.

Application October 5, 1946, Serial No. 701,487

s 6 Claims.

This invention relates to doctor blades and in,

hemmed curtains, where-the material is doubled at the side and end hems, and especially at the corners where the hems overlap and the material is four times as thick as in thepanel portion of the curtain, the hard rigid doctor blade scrapes too hard against that portion of the stencil overlying the thickened portions otthe material. i

These high spots in the material being printed, cause the stencil to press 'harder against the scraper at these points which produces excessive wear to the stencil. This. injurious scraping against the high spots is especially'serious when harm to the stencil because the rubber compresses or expands with the undulations'of the hem and the fiber prevents the rubber from wearing down; and to provide a doctor blade structure that greatly prolongs'the life of the stencils which are both difilcult and expensive to make and one that can be applied to blades used in the coating of fabrics or the printing processes and may be used at spaced points along the edge of the blade or entirely across the width of the same.

Other objects and structural details of the invention will be apparent from the following description when read in connection with the accompanying drawing, wherein Figure l is a view in perspective of a fragment of material being printed upon, the stencil being indicated in outline and my improved doctor blade being shown in position of yield with respect printing finished hemmed curtains; table-cloths, I

handkerchieis and the like, because the article to be printed must always be placed in the same position beneath and with respect to the stencil so that the printed design will be placed correctly on the article being printed upon. This brings the high spots always in the same place and causes the stencil to wear out very rapidly at these points.

While I am aware that scrapers have been made from various materials, it has been found that rubber blades or those tipped or edged with rubber not only do not give as clean and sharp an impression as the hard scraper but wear rapidly away and require constant adjustment or frequent replacement.

The important object of my invention, there fore, is to provide a blade structure that'greatly minimizes this serious scraping action; that makes use of the rigid blade as a body and to which are attached rubber and flexible fiber strips in such arrangement and relation to the metal blade that, when the necessary pressure required for printing or coating is applied to the doctor blade, the rubber compresses and the fiber stri becomes the scraping edge; to provide a blade that will give a sharp hard edge on the flat part of the material to be printed, while the rubber backed, thin flexible fiber rides over the thick uneven hem of the curtain or the like without to the hem of a panel,

Figure 2 is a view in perspective of the reverse side of the doctor blade as seen in Figure 1,

Figure 3 is a-viewin end elevation of a, doctor blade constructed in accordance with my invention and adapted for use as a full length blade or as a section of a blade,

Figure 4 is a view in perspective of an end of the blade showing the recessed corner thereof for the reception of the fiber and rubber strips, and

Figure 5 is a view in side elevation of a blade constructed throughout its length in accordance with my invention. 4

Referring to the drawing in detail, l0 indicates 'a curtain panel having a hemmed edge II, the

panel and hem being printed upon through the use of any of the well known stencil mounting means, such as the sleeve type, the cylinder type or the flat stencil screen or cutout. The stencil is indicated as at 12, in outline, to show that the doctor blade structure presses thereagainst to force the stencil against the work Ill. The device to be described comprises a holder IS in which is clamped along one edge, a metalblade l4, having as shown in Figure 4, a cut-out i5 at one end thereof providing a recess into which the turned under lower edges of a strip of rubber i8 and a strip of thin flexible fiber I! extend to fill the space left by the metal that was removed so that the blade is complete and presents an unbroken even lower edge throughout its length. While the cut-out portion 1'5 is indicated as at one edge or end, it is understood that it may be formed at any point in the length of the blade as desired and as many times as is necessary to allow for thickened parts of the panel that the blade may have to ride over. As shown in Figure 5, the clamp 20 holds the metal blade ii to which is attached the rubber strip 22 and the thin flexible flber strip I3 so that both of the latter extend below and turn under the bottom edge of the blade II to provide a blade that may be used either in coating or printing and one which will compensate at all points for uneven surfaces over which it is drawn or beneath which said surfaces pass.

The rubber and flber strips are attached to the blade by the use of a keeper strip 24 which may be secured to the blade by the screws 25 or other holding media. v

It is evident that the blade structure referred to may be used manually or in a machine for printing or coating purposes and that when used as shown in Figure 1, it will, by compression of the rubber strip l6, relieve the scraping pressure that increases at the point or zone in the stencil beneath which passes the hem or other protuberant portion of the material being printed upon.

When I have described what I consider to be a highly desirable embodiment of my invention, it is obvious that changes in form could be made without departing from the spirit of my invention, and I therefore, do not limit myself to the exact form herein shown and described, nor to anything less than the Whole of my invention as hereinbefore set forth, and as hereinafter claimed.

What I claim as new and desire to secure by Letters Patent is:

l. A doctor blade structure for use in printing and like machines for spreading matter to be applied to a surface having uneven portions comprising a metal blade presenting a longitudinally extending lower edge for normal engagement with a stencil in engagement with said surface, said blade having a cut-out portion in said lower edge, a piece of rubber in strip form attached to said blade, a strip of fiber secured to said rubber and extending therebeyond at the lower edge of said blade for engagement with the stencil, and said rubber and fiber strips filling the space afforded by said cut-out for yielding to an inward movement of the stencil as it passes over an uneven surface of said material.

2. A doctor blade comprising a body strip of inflexible material shaped to provide a recessed lower edge, a flexible strip, a pliable strip, means for mounting said flexible and pliable strips to said body strip, said pliable strip being interposed between the flexible strip and the body strip and beyond said pliable strip to provide a yieldably rigid wiping edge and the edge of said pliable strip providing a cushion between said wiping edge and the lower edge of the body strip in wiping action.

4. In a device of I the character described, a metal blade having a recessed lower edge, rubber and flber strips, means for securing said rubber and fiber strips to one face'of the blade with the lower ends thereof extending through the recess and laterally of the lower edge of said metal blade.

5. In a device of the character described, a metal blade having a recessed lower edge, rubber and fiber strips, means for securing the rubber and fiber strips to one face of the blade, said rubber strip being interposed between the blade and the fiber strip, and the lower edges of said strips being turned into said edge recess and extended laterally beyond the lower edge of said blade.

6. In a device of the character described, a metal blade having a recessed lower edge, rubber and flber strips, means for securing said strips to a face of the blade, said rubber strip being interposed between the fiber strip and said blade, and both strips extending downwardly below the bottom edge of said blade and being bent therebeneath and in said recessed lower edge to provide a, yieldable wiping edge completing the bottom edge of said blade.

CHARLES A. HANINGTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Hawrylasz Mar. 29, 1938 Number 

